<script setup>
    import {ref} from "vue"
    let sum = ref(1);
    let n = ref(1);
    
    function add() {
        console.log(n.value);
        sum.value += n.value;
    }
    function sub() {
        console.log(n.value);
        sum.value -= n.value;
    }
</script>

<template>
    <div>
        <h2>当前求和为 {{sum}}</h2>
        <select v-model.number="n">
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
        </select><br>
        <button @click="add">加</button>
        <button @click="sub">减</button>
    </div>
</template>

<style scoped>

</style>